Device for the fine adjustment of microscopes.



F. MEYER.

DEVICE FOR THE FINE ADJUSTMENT 0F MIGROSGOPES. APPLICATION FILED MAY 7,1914.

LlU6,95 PatentedAuglLlQM however, by as accurate work as possible, the

UNITED STATES 1 FRANZ MEYER, 0E JENA, GERMANY, assleivoia TO THE EIEM 0FCARL ZEISS, 0E JENA, GERMANY.

, DEVICE FOR THE FINEEADJ'USTMENT OF MICROSCOPES.

. Specification of Letters Patent.

Patented Aug. till, 1914.

Application flTedMay 7, 1914. Serial No. 836,959.

To all whom it may concern Be it known that I, FRANZ MEYER, a" citizenof the German Empire, residing at Jena, Germany, have invented a new anduseful Device forthe 'Fine Adjustment'of Microscopes, of which thefollowing is a specification. The invention relates to a device for thefine adjustment of the tube, necessary with microscopes. In practice anumber of con struction's are used for this adjustment, all of whichagree in principle in this respect, that the motion of the tube isefiected with the aid of a carefully cut micrometer-screw. Formicroscopes of small and medium power it suflices with suchconstructions, for the drive of the screw or of its nut to be eifectedby a milled disk; for those of greater power the necessary moreaccurate, adjustment is obtained by connecting thescrew or the nut witha worm wheel and actuating the latter by means of a-worm. All theseconstructions have the drawback, that the manufacture of themicrometer-screw is comparatively costly on account of the careful workthat must be put into it. The constructions with direct drive of themicrometer-screw have the further disadvantage, that the actuating disksfor the coarse and fine adjustment lie in two planes, which areperpendicular to one another, which results in the instrument beingawkward to work with. While in the constructions with worm and wormwheelthis may be easily avoided, the total elimination of back-lashpresentsconsiderable diiiiculties. Various attempts have been made with theselatter constructions to render any play, which may appear, harmless bymeans of springs; through the constantly acting spring-pressure,however, the lubricating material is gradually pressed away fromthe'faces of the teeth, whereby intime a hard, uneven travel is caused.If,

worm gearing is. to be made entirely with out play, it will prove verycostly. These difliculties anddrawbacks are avoided in the new adjustingdevice, by efiecting the motion of the tube not by means of a screw orworm, but 'wj ith the aid of toothed gearing. For this purpose the tube,which is guided in a straight line in the well-known manner, isconnected with a lever disposed. within the fixed support, -which levercarries a toothed segment, which is concentric with the fixed center ofrotation of the lever, and engages by means of the said segment with amultiple toothed wheel gearing; the device is actuated by the last shaftof the gearing, which is carried through to the outside, by means of oneor of two milled edged disks. In order to avoid all back-lash, the tubewill be pressed in the usual way by a spring bearing against the fixedsupport onto the lever, by which means all the gear wheels will contactwith one another permanently with the same tooth faces. Experiments haveshown, that the friction'in the guiding bearings of the driving shaftentirely suffices to render the device self stopping. In orderto makeaccuracy in the manufacture of the toothing possible, spur-wheelgearings will be employed in most cases.

, In the annexed drawing a constructional form of the invention is shownas applied to a normal microscope, Figure 1 being an elevation of theupper part of the microscope, the new device being shown partly insection, and Fig. 2 being a cross-section on line 22 of 1.

A microscope tube a is in the first place provided with a well-known,frequently constructed device for its coarse adjustment. A guide bar I),which is screwed to the tube a, carries a rack 6 which engages withtoothed gearing not visible in the drawing, on the shaft of which arefixed two milled edged disks b one of which just covers the other inFig. 1. The bar 6 slides in a slot in a guiding piece 0, which carriesthe bearing of the toothed gearing of the coarse adjustment and at thesame time forms the movable part of the fine adjustment device. For thispurpose the part c is formed as. a slide and is guided on a fixedsupport part d in a straight line parallel to the axis of the tube. Themotion-giving device for the fine adjustment is mounted in a hollowspace 69 of the support d. On a knife-edge e fixed to the support atthere rests a lever which is in the plane of symmetry of the microscopeand one end of which supports the slide 0 by its projection by means ofa connecting bar g. which is journaled at both ends in centers. By meansof a spring IL the slide 0 is pressed permanently onto the lever f. Theother endof the lever f carries a toothed segment i and engages by meansofthe latter with toothed gearing k, the motion of which is stronglymagnified by a double spur-wheel gearing consisting of the pairs ofWl18QlSZ ,Z and 112), m The gearing shafts are journaled in the casingd; the shaft of the small driving Wheel m is produced at both ends tothe outside and carries two milled heads at.

I claim:

In a microscope a tube, a tube-carrier and a stand, means for a coarseadjustment and means for a fine adjustment between the said tube and thesaid stand, the latter means comprising a lever fulcrumed Within thesaid stand, a toothed segment on the said lever, having its center inthe fulcrum of the said lever, multiple toothed wheel gearing journaledin the said stand and meshing with the said segment, means for actuatingthe said gearing and spring-controlled connecting means between thelever and the tube-carrier, adapted to transmit the movements of thelever to the tube-carrier.

FRANZ MEYER. Witnesses:

)AUL KRI'joER, FRITZ SANDER.

